Polyvinyl acetate encapsulation of crystalline sucralose for use in chewing gum

ABSTRACT

A sucrose-containing chewing gum ingredient is prepared by homogeneously mixing about 50 to about 97 parts by weight heat-softened polyvinyl acetate with about 3 to about--50 parts by weight crystalline sucralose. The mixture is then cooled. A chewing gum is prepared by mixing the sucralose-containing ingredient, gum base, a bulking agent and flavor to make a chewing gum composition.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of Application PCT/US89/05296, filed Nov. 22, 1989 and titled Method of Controlling Release of Sucralose in Chewing Gum and Gum Produced Thereby, the disclosure of which is hereby incorporated by reference. This application is also a continuation-in-part of U.S. patent application Ser. No. 07/418,662, filed Oct. 10, 1989 now abandoned and U.S. patent application Ser. No. 07/340,384, filed Apr. 19, 1989 (now U.S. Pat. No. 4,978,537), both of which are also hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to chewing gum, and more particularly to the use of a polyvinyl acetate encapsulated crystalline sucralose in chewing gum.

BACKGROUND OF THE INVENTION

Chewing gums comprise many ingredients, including sweeteners. Sweeteners suitable for chewing gums include both natural and artificial sweeteners. Recently, high-intensity sweeteners have been the focus of investigation for use in chewing gum.

High-intensity sweeteners may be hundreds of times sweeter than natural sweeteners such as sucrose and glucose. High-intensity sweeteners of recent interest include aspartame, acesulfame K, cyclamates, saccharin, and now sucralose. Sucralose is a new, high-intensity sweetener which is a tri-chlorinated sucrose derivative and is about 400-800 times sweeter than sucrose. Sucralose has been reported to be cheaper than aspartame and at least 3 times sweeter. Compared to some other high-intensity sweeteners, sucralose has a sweet taste more similar to sucrose. Chemically, sucralose is known as 4,1',6'-trichloro-4,1',6'-trideoxy-galactosucrose, or alternatively 1,6-dichloro-1,6'-dideoxy-(β)-D-fructofuranosyl 4-chloro-4-deoxy-(α)-D-galactopyranoside. The United States Food and Drug Administration is now considering sucralose as a food additive. The manufacturer of sucralose is Tate & Lyle, Inc. in the U.K. Sucralose is marketed in the United States by McNeil Specialty Products Co., Skillman, N.J. Its use to sweeten substances, including oral compositions, is disclosed in U.S. Pat. Nos. 4,343,934 and 4,389,394, both of which are incorporated herein by reference. The use of sucralose as an artificial sweetener is also disclosed in U.K. Patent Nos. 2,065,646; 2,065,648 and 2,153,651.

The use of sucralose in chewing gum has been disclosed in other patents.

U.S. Pat. No. 4,495,170 discloses sweetener mixtures for use in foods, beverages and pharmaceuticals but not specifically chewing gums. The mixtures are of sucralose and aspartame, saccharin, and acesulfame K. U.S. Pat. No. 4,389,394 discloses the use of artificial sweeteners in chewing gum to prevent dental caries. Chlorinated sucrose derivatives are disclosed in U.S. Pat. Nos. 4,435,440; 4,549,013; and 4,612,373.

U.K. Patent No. 2,154,850 discloses beverages sweetened with sucralose and cyclamate (among others).

U.K. Patent No. 2,185,674 discloses combinations of thaumatin and sucralose (among others) to stimulate growth of farm animals.

U.S. Pat. No. 4,820,528 discloses co-dried sucralose and acid saccharin to prolong sweetness release.

One of the limitations of chewing gum is that the sweetness and flavor are rapidly lost during chewing. Thus, chewing gum producers are constantly trying to extend the time in which a consumer of chewing gum can enjoy its flavor and sweetness.

Patents disclose how a sweetener like aspartame can be physically modified to control the release rate in chewing gum.

For example, U.S. Pat. No. 4,597,970 to Sharma et al. teaches a process for producing an agglomerated sweetener wherein the sweetener is dispersed in a hydrophobic matrix consisting essentially of lecithin, a glyceride, and a fatty acid or wax having a melting point between 25° and 100° C. The method disclosed uses a spray-congealing step to form the sweetener-containing matrix into droplets, followed by a fluid-bed second coating on the agglomerated particles.

U.S. Pat. Nos. 4,515,769 and 4,386,106, both to Merrit et al., teach a two step process for preparing a delayed release flavorant for chewing gum. In this process, the flavorant is prepared in an emulsion with a hydrophilic matrix. The emulsion is dried and ground and the particles are then coated with a water-impermeable substance.

U.S. Pat. No. 4,230,687 to Sair et al. teaches a process for encasing an active ingredient to achieve gradual release of the ingredient in a product such as chewing gum. The method described involves adding the ingredient to an encapsulating material in the form of a viscous paste. High-shear mixing is used to achieve a homogeneous dispersion of the ingredient within the matrix, which is subsequently dried and ground.

U.S. Pat. No. 4,139,639 to Bahoshy et al. teaches a process of "fixing" aspartame by co-drying (by spray drying or fluid-bed coating) a solution containing aspartame and an encapsulating agent, such as gum arabic, to thereby surround and protect the aspartame in the gum during storage.

U.S. Pat. No. 4,384,004 to Cea et al. teaches a method of encapsulating aspartame with various solutions of encapsulating agents using various encapsulation techniques, such as spray drying, in order to increase the shelf-stability of the aspartame.

U.S. Pat. No. 4,634,593 to Stroz et al. teaches a method for producing controlled release sweeteners for confections, such as chewing gum. The method taught therein involves the use of an insoluble fat material which is mix mulled with the sweetener.

PCT Publication WO 90/07859 discloses a number of techniques, including encapsulation techniques, for delaying the release of sucralose from chewing gum. In example 18 of the publication, sucralose is mixed with polyvinyl acetate and the combined material is added to other gum base ingredients and made into gum.

It is known that the sweetness and flavor can be extended in chewing gum by using high levels of high intensity sweeteners such as aspartame. The extension properties of those sweeteners, however, are limited by their release characteristics during chewing of the gum. Providing a chewing gum having improved sweetness and flavor extension is one object of this invention.

Sucralose, when modified according to the present invention and incorporated into chewing gum, gives a chewing gum having a controlled-release sweetener. A higher quantity of sweetener can be used without resulting in excessive initial sweetness, but instead having a delayed sweetness release, giving a highly consumer-acceptable chewing gum product.

SUMMARY OF THE INVENTION

The present invention includes sucralose-containing chewing gum ingredients and methods of making the ingredients. The methods include the steps of homogeneously mixing about 50 to about 97 parts by weight heat-softened polyvinyl acetate (PVAc) with about 3 to about 50 parts by weight of crystalline sucralose. The homogeneous mixture is then cooled, leaving a solid, blended ingredient.

The invention also includes chewing gum compositions containing the sucralose-containing ingredients and methods of making the gum. The gum making methods include the steps of providing the sucralose-containing ingredient as outlined above, and mixing the same with gum base, a bulking agent and flavoring agent to make a chewing gum composition.

It has been found that the sucralose incorporated in chewing gum using the sucralose-containing ingredient of the present invention is extremely slow to release from the gum. Thus the invention provides a very simple but effective delay release mechanism for sucralose.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

As used herein, the term "chewing gum" includes chewing gum, bubble gum andthe like. Unless specified otherwise, all percents used herein are weight percents.

The first step in preparing the sucralose-containing ingredient of the present invention is to homogeneously mix heat-softened PVAc and crystalline sucralose. The PVAc used in the present invention will be a food grade polymer. The molecular weight of the polymer is not believed tobe critical to working of the invention, but certain molecular weights may be easier to use to produce the blended ingredient and others may be more effective at extending the release rate of sucralose. Specifically, lower molecular weights of PVAc tend to be easier to mix and reduce the effort necessary to clean out the mixing apparatus afterwards. However, there is some evidence that higher molecular weights provide slightly slower release.

The contemplated molecular weight range of PVAc usable in the present invention is from about 7000 to about 100,000 molecular weight units (MWU). The preferred range is from about 10,000 MWU to about 50,000 MWU and most preferred are polymers of about 15,000 MWU to about 32,000 MWU. (The preceding molecular weight numbers are based on average molecular weight as measured by Gel Permeation Chromatography. Other methods of measuring molecular weights of polymers may give substantially different values.)

The level of sucralose used in the PVAc blend can vary greatly. An upper limit would be just below the amount where the sucralose loading is so high that the PVAc can no longer form a film upon cooling. Levels in the range of about 3% to about 50% are specifically contemplated, while about 15% to about 35% is preferred. The most preferred level is about 20% to about 30%. The exact level chosen will depend on the intended usage level of this ingredient in the final gum composition.

A variety of methods of preparing the sucralose blends of the present invention are contemplated. A fiber spinning method as disclosed in U.S. patent application Ser. No. 07/418,662 and U.S. Pat. No. 4,978,537 may be used. The PVAc/sucralose blend may also be mixed in a conventional sigma blade gum mixer. Any other type of mixer suitable for the task may also beused. Usually heat will be used to soften the PVAc to aid mixing. Preferredtemperatures for mixing are in the range of 100° to 212° F.

A preferred mixing method uses a heated extruder to blend the dry ingredients then melt or soften the PVAc. The homogenous mixture is then discharged from the extruder. The mixture may also be made by first heat-softening the PVAc and then adding the crystalline sucrose. After themixing process, the blended ingredient must be cooled.

After cooling, the ingredient is preferably sized, usually by grinding and/or sieving to provide the desired particle size. The particle size should be small enough so as not to be noticeable in the finished gum. Excessively fine particles may lose some of the slow release benefit, but in practice, this is not a serious problem. The preferred particle size isless than about 420 microns. Usually a size range of about 80 microns to about 400 microns is desirable.

The usage level of the encapsulated ingredient in gum will vary with the active level of sucralose in the encapsulation. In general, the usage level will be calculated to give a desired level of active sucralose in the gum. Usage levels of the encapsulated ingredient of about 0.02 percentto about 20 percent are therefore contemplated. The actual optimized usage level may be higher than might be theoretically calculated due to the slower release rate of the blended ingredient. Depending on the desired sweetness level and the presence of other sweeteners in the gum, the active sucralose level may vary from about 0.01% to about 0.50% or even higher.

In general, a chewing gum composition typically comprises a water-soluble bulk portion, a water-insoluble chewable gum base portion and typically water-insoluble flavoring agents. The water-soluble portion dissipates with a portion of the flavoring agent over a period of time during chewing. The gum base portion is retained in the mouth throughout the chew.

The insoluble gum base generally comprises elastomers, resins, fats and oils, waxes, softeners and inorganic fillers. Elastomers may include polyisobutylene, isobutylene-isoprene copolymer and styrene butadiene rubber, as well as natural latexes such as chicle. Resins include polyvinyl acetate and terpene resins. Fats and oils may also be included in the gum base, including tallow, hydrogenated and partially hydrogenatedvegetable oils, and cocoa butter. Commonly employed waxes include paraffin,microcrystalline and natural waxes such as beeswax and carnuba. According to the preferred embodiment of the present invention, the insoluble gum base constitutes between about 5 to about 80 percent by weight of the gum.More preferably the insoluble gum base comprises between 10 and 50 percent by weight of the gum and most preferably about 20 to about 35 percent by weight of the gum.

The gum base typically also includes a filler component. The filler component may be calcium carbonate, magnesium carbonate, talc, dicalcium phosphate or the like. The filler may constitute between about 5 and about60 percent by weight of the gum base. Preferably, the filler comprises about 5 to about 50 percent by weight of the gum base.

Gum bases typically also contain softeners, including glycerol monostearateand glycerol triacetate. Further, gum bases may also contain optional ingredients such as antioxidants, colors, and emulsifiers. The present invention contemplates employing any commercially acceptable gum base.

The water-soluble portion of the chewing gum may further comprise softeners, sweeteners, flavoring agents and combinations thereof. Softeners are added to the chewing gum in order to optimize the chewability and mouth feel of the gum. Softeners, also known in the art asplasticizers or plasticizing agents, generally constitute between about 0.5to about 15.0 percent by weight of the chewing gum. Softeners contemplated by the present invention include glycerin, lecithin, and combinations thereof. Further, aqueous sweetener solutions such as those containing sorbitol, hydrogenated starch hydrolysates, corn syrup and combinations thereof may be used as softeners and binding agents in gum.

The sucralose-containing ingredient of the present invention will most likely be used in sugarless gum formulations. However, formulations containing sugar are also within the scope of the invention. Sugar sweeteners generally include saccharide-containing components commonly known in the chewing gum art which comprise, but are not limited to, sucrose, dextrose, maltose, dextrin, dried invert sugar, fructose, levulose, galactose, corn syrup solids and the like, alone or in any combination. Generally sugarless sweeteners include components with sweetening characteristics but which are devoid of the commonly known sugars and comprise, but are not limited to, sugar alcohols such as sorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, maltitol and the like, alone or in any combination.

These sugar and sugarless sweeteners often also serve the role as bulking agents in chewing gum. The bulking agent generally comprises from about 5 percent to about 80 percent of the gum composition.

Depending on the particular sweetness release profile and shelf-stability needed, the sucralose-containing ingredient of the present invention can also be used in combination with uncoated high-potency sweeteners or with high-potency sweeteners coated with other materials and by other techniques. In particular, sucralose treated to increase its release rate as described in U.S. Pat. No. 4,986,991, incorporated herein by reference,may be used in conjunction with the present invention.

A flavoring agent may be present in the chewing gum in an amount within therange of from about 0.1 to about 10.0 weight percent and preferably from about 0.25 to about 5 weight percent of the gum. The flavoring agents may comprise essential oils, synthetic flavors, or mixture thereof including, but not limited to, oils derived from plants and fruits such as citrus oils, fruit essences, peppermint oil, spearmint oil, clove oil, oil of wintergreen, anise, and the like. Artificial flavoring components are alsocontemplated for use in gums of the present invention. Those skilled in theart will recognize that natural and artificial flavoring agents may be combined in any sensorially acceptable blend. All such flavors and flavor blends are contemplated by the present invention.

Optional ingredients such as colors, emulsifiers and pharmaceutical agents may be added to the chewing gum.

In general, chewing gum is manufactured by sequentially adding the various chewing gum ingredients to a commercially available mixer known in the art. After the ingredients have been thoroughly mixed, the gum mass is discharged from the mixer and shaped into the desired form, such as by rolling into sheets and cutting into sticks, extruding into chunks or casting into pellets.

Generally, the ingredients are mixed by first melting the gum base and adding it to the running mixer. The base may also be melted in the mixer itself. Color or emulsifiers may also be added at this time. A softener such as glycerin may also be added at this time, along with syrup and a portion of the bulking agent. Further portions of the bulking agent may then be added to the mixer. A flavoring agent is typically added with the final portion of the bulking agent.

The entire mixing procedure typically takes from five to fifteen minutes, but longer mixing times may sometimes be required. Those skilled in the art will recognize that many variations of the above described procedure may be followed.

The blended sucralose-containing ingredient may be added at any point in the gum making process. The preferred point is with the first bulk sweetener addition. Very early addition into hot base is undesirable sincethe PVAc may soften or melt.

EXAMPLE 1

Sixty grams of ground PVAc (MW=32,000) were softened in a small, heated sigma blade mixer. Fifteen grams of ground crystalline sucralose were added to the mixer and mixing was continued until the mixture was homogeneous, about eight minutes. The mixture was then cooled and ground in a Fitzmill grinder with a 0.109 inch screen. The ground ingredient was sieved and the fraction between 40 and 135 U.S. standard mesh size was used. Theoretically the ingredient contained 20% sucralose.

EXAMPLE 2 (COMPARATIVE EXAMPLE)

The method of Example 1 was repeated except that acesulfame-K was substituted for sucralose.

EXAMPLES 3, 4, 5 (CHEWING GUMS)

Chewing gums were made according to the following formulas (in percent by weight).

    ______________________________________                                                            Comparative                                                                               Comparative                                                 Example 3                                                                              Example 4  Example 5                                        ______________________________________                                         Sugar        53.455    53.455     53.695                                       Base         22.255    22.255     22.255                                       Corn Syrup   5.130     5.130      5.130                                        Glycerin     2.000     2.000      2.000                                        Calcium Carbonate                                                                           2.000     2.000      2.000                                        10% Salt Solution                                                                           0.100     0.100      0.100                                        Dextrose     13.410    13.410     13.410                                       Spearmint Flavor                                                                            1.350     1.350      1.350                                        Ingredient of Ex. 1                                                                         0.300     --         --                                           Ingredient of Ex. 2                                                                         --        0.300      --                                           Crystalline Sucralose                                                                       --        --         0.060                                                     100.000   100.00     100.000                                      Active Sweetener                                                                            0.060     0.060      0.060                                        ______________________________________                                    

Note that Example 5 is a practicing of one aspect of the invention disclosed in U.S. Pat. No. 4,986,991 as the base composition is one which was found to delay the release of sucralose.

SENSORY TESTING

The gums of Examples 3 and 5 were compared in a 20 minute chew for sweetness duration. Six trained panelists chewed the samples along with two other samples not related to the present test. The samples were blind coded and presented in random order. The panelists ranked the samples fromgreatest to least sweetness duration. The panelists also made additional comments on the samples. The average rankings (1 being the longest-lasting, 4 the shortest) were:

    ______________________________________                                                           Average                                                                        Order Ranking                                                ______________________________________                                         Gum of Example 3 (inventive)                                                                       2.1                                                        Gum of Example 5 (control)                                                                         3.5                                                        ______________________________________                                    

Panelists noted a faster decline of sweetness and flavor intensity in Examples 5 and fluctuations in the late sweetness level in both samples but especially in Example 5. Example 3 was described as having better sweetness character than Example 5. These results show that the inventive ingredient performs well when compared to sucralose mixed directly into gum with a base composition known to delay the release of the sucralose.

ANALYTICAL RELEASE RATE

The gums of Examples 3 and 4 were chewed by several individuals for 0, 2, 5, 10 and 20 minutes. The cuds were collected and analyzed for residual sweetener to determine the release rates. The results are tabulated below.

                  TABLE 1                                                          ______________________________________                                         Chew Out Test Results                                                                         Level % of Orig.                                                               %     Remaining                                                 ______________________________________                                         Example 3 (Inventive: Sucralose, 20% Loading):                                 Theoretical (0 min.)                                                                            0.060   --                                                    Analyzed (0 min.)                                                                               0.053   100                                                   2 min.           0.050   94                                                    5 min.           0.050   94                                                    10 min.          0.054   102                                                   20 min.          0.043   81                                                    Example 4 (Comparative: Acesulfame K, 20% Loading):                            Theoretical (0 min.)                                                                            0.060   --                                                    Analyzed (0 min.)                                                                               0.044   100                                                   2 min.           0.040   91                                                    5 min.           0.036   82                                                    10 min.          0.032   73                                                    20 min.          0.017   39                                                    ______________________________________                                    

In previous test with similar gum formulas, with crystalline sucralose mixed directly into the gum, some of which are disclosed in U.S. Pat. No. 4,986,991, the gum retained approximately 20% of its original sucralose level after 20 minutes of chewing. Ethanol and aqueous solutions of sucralose mixed directly into gum produced gums that retained less than 10% of their original level after 20 minutes of chewing. Thus, in comparison, the results in Table 1 show that the crystalline sucralose encapsulated by PVAc has a significantly delayed release from chewing gum when compared to these other methods of mixing sucrolose in gum. In fact, the present invention is more effective in prolonging release than the slow release base formulas previously disclosed. With the present invention, a chewing gum can be prepared which retains over 60% of the original sucralose after 20 minutes of chewing.

The results of Table 1 also show that the invention is uniquely suited for sucralose encapsulation. When acesulfame K, a sweetener with similar watersolubility, is subjected to the same treatment steps, the resulting gum does not exhibit the same surprising delayed release of the acesulfame K.

In addition to slowing the release rate of sucralose from gum during chewing, the present invention offers certain other practical benefits. The volume of material added is increased by the bulking effect of the PVAc, allowing easier and more homogeneous mixing into the gum. The PVAc/sucrolose ingredient is stable both when stored as an ingredient and in the gum. This is in contrast to dry, crystalline sucralose, which is somewhat unstable under certain conditions.

It should be appreciated that the compositions and methods of the present invention are capable of being incorporated in the form of a variety of embodiments, only a few of which have been illustrated and described above. The invention may be embodied in other forms without departing fromits spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive, and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

We claim:
 1. A method of producing chewing gum comprising the steps of:a) providing a blended, sucralose-containing ingredient byi) homogeneously mixing about 50 to about 97 parts by weight heat-softened PVAc with about 3 to about 50 parts by weight of crystalline sucralose and ii) cooling the homogeneous mixture to a solid form, and b) mixingi) about 0.02% to about 20% by weight of the chewing gum of the blended sucralose-containing ingredient, ii) about 5% to about 80% by weight of the chewing gum of a base, iii) about 5% to about 80% by weight of the chewing gum of a bulking agent, and iv) about 0.25% to about 5% by weight of a flavoring agent to make the chewing gum composition.
 2. The method of claim 1 wherein the sucralose and PVAc are blended prior to heat-softening the PVAc.
 3. The method of claim 1 wherein the PVAc is heat softened prior to the blending of the sucralose and the PVAc.
 4. The method of claim 1 further comprising the step of sizing the blended ingredient to a particle size of less than about 420 microns.
 5. The method of claim 1 wherein the blended ingredient has a sucralose level of between about 3% and about 50%.
 6. The method of claim 1 wherein the blended ingredient has a sucralose level of between about 15% and about 35%.
 7. The method of claim 1 wherein the blended ingredient has a sucralose level of between about 20% and about 30%.
 8. The method of claim 1 wherein the PVAc has an average molecular weight of between about 7000 MWU and about 100,000 MWU as measured by Gel Permeation Chromatography.
 9. The method of claim 1 wherein the PVAc has an average molecular weight of between about 10,000 MWU and about 50,000 MWU as measured by Gel Permeation Chromatography.
 10. The method of claim 4 wherein the blended, dried ingredient is sized to less than about 420 microns.
 11. The method of claim 4 wherein the blended, dried ingredient is sized to between about 80 microns and about 400 microns.
 12. The method of claim 1 wherein the level of sucralose in the gum is between about 0.01% and about 0.5%.
 13. A method of making a sucralose-containing ingredient for chewing gum comprising the steps of:a) homogeneously mixing about 50 to about 97 parts by weight heat-softened PVAc with about 3 to about 50 parts by weight of crystalline sucralose and b) cooling the homogeneous mixture to provide a solid, blended ingredient.
 14. The method of claim 13 further comprising the step of sizing the blended ingredient to a particle size of less than about 420 microns.
 15. The method of claim 13 wherein the sucralose and PVAc are blended prior to heat-softening the PVAc.
 16. The method of claim 13 wherein the PVAc is heat softened prior to the blending of the sucralose and the PVAc.
 17. A chewing gum containing PVAc encapsulated crystalline sucralose, the encapsulation being sufficient such that over 60% of the sucralose remains in the gum after twenty minutes of chewing.
 18. A chewing gum composition made according to the method of claim
 1. 